Design and fabrication of a lifting triangle
In building a bridge over an active line in a location with limited access, Blythe Construction needed to find a way to vertically lift and set five 65-tonne, 140’-long (42.7 m) girders without encroaching on the railroad tracks or affecting rail schedules.
A specially fabricated lifting triangle is used to transfer the load between two cranes located on either side of the rail track. At the start of the operation, the first crane raises the end of the girder and moves it over the rail track. The lifting triangle is then used to transfer the load supported by the first crane to the second. The first crane is then free to lift the other end of the girder and place it in its final position.
All five girders were able to be set in eight hours with no stoppages or delays of trains
travelling along the rail tracks. The operation met all safety goals with no incidents or injuries. The lifting triangle makes it possible to use cranes with lower lifting capacity with minimal hands-on contact by team members.
This conception was awarded a Special keep it simple prize in the Materials, Processes and Techniques category.